We had this exact problem last Aug - and for the same reason.
Our flight arrived at something like 11:30 pm the day before we were to check in at OKW. I got a room at Ramada Maingate West (here's the review I did:
http://www.disboards.com/showthread.php?t=1556255) for something like $60.
We could have stayed at SoG, but decided to save the extra $$$ by staying off site. We basically just need bed rental. SoG is VERY nice, BTW and I recommend it highly.
We did get a car - because our arrival time was so late - that's what made sense. We got it from
Avis as we could turn it in at the Marriott (nearly) across the street from DTD. Besides - that gave us wheels to get our grocery shopping done. So, it was a single day (24 hour) rental. That wound up being cheaper than either a cab or getting a service.
We didn't plan on Day 1 (the day after our very late arrival) being a park day since we were all jet lagged, tired, and getting organized for our stay. Since we were staying 10 days - it wasn't a huge loss. And it was nice to sort of ease into our vacation.
Since we arrived at the resort well before our room was ready (about noon) we hung out at the Community Center and had a BALL! This is an under utilized gem! We had swimming gear, but didn't use it. When the room was ready - move in all our gear. And one parent unpacked while the other went for groceries. Then we turned in the car.
I'd do it again - it worked out really well for us. (Mom, Dad, and two boys aged 10 and 6 at the time.)
